Remove incorrect init special case for wikitext single edit tab

This line was added in 9eebfbcac5
and I can't tell what it was supposed to do (that commit's message
only says "Fix NWE-only edit tab", thanks a lot).

Since then the init code was refactored a lot, at some point this
line was moved to be a part of a completely different check (???),
and now it's causing visual mode to be disabled even though the
user only set their preferences to *prefer* wikitext mode.

Bug: T243723
Change-Id: I3c1f502c3cd079fc5eeb2e9587b22d854ae3a72c

modules/ve-mw/preinit/ve.init.mw.DesktopArticleTarget.init.js

@@ -1022,10 +1022,7 @@
 		// User has 'visualeditor-enable' preference enabled (for alpha opt-in)
 		// User has 'visualeditor-betatempdisable' preference disabled
 		// User has 'visualeditor-autodisable' preference disabled
-		enable && !tempdisable && !autodisable &&
-
-		// Except when single edit tab for old wikitext
-		!( conf.singleEditTab && tabPreference === 'prefer-wt' && !init.isWikitextAvailable )
+		enable && !tempdisable && !autodisable
 	);
 
 	// Duplicated in VisualEditor.hooks.php#isVisualAvailable()